#include <bits/stdc++.h>

#define int long long

struct BaseVector2 : public std::pair<int, int>
{
#define x first
#define y second
    using std::pair<int, int>::pair;

    BaseVector2 operator-(BaseVector2 a) const
    {
        return BaseVector2(this->x - a.x, this->y - a.y);
    }
    int operator*(BaseVector2 a) const
    {
        return this->x * a.x + this->y * a.y;
    }
    int operator%(BaseVector2 a) const
    {
        return this->x * a.y - this->y * a.x;
    }
    friend std::istream &operator>>(std::istream &in, BaseVector2 &p)
    {
        return in >> p.x >> p.y;
    }
};

int dis2(BaseVector2 a, BaseVector2 b = BaseVector2(0, 0))
{
    BaseVector2 p = a - b;
    return p * p;
}

using Point = BaseVector2;
using Vector = Point;

int sgn(BaseVector2 p)
{
    if ((p.x < 0 or p.x == 0 and p.y > 0))
    {
        return true;
    }
    return false;
}
bool polarCmp(Vector p, Vector q)
{
    if (sgn(p) == sgn(q))
    {
        if (p % q == 0)
        {
            return dis2(p) < dis2(q);
        }
        else
        {
            return p % q > 0;
        }
    }
    return sgn(p) < sgn(q);
}
const long double pi = acosl(-1.0);

long double getAngle(Point a, Point b, Point c)
{
    auto v1 = b - a, v2 = c - a;
    return atan2l(v1 % v2, v1 * v2);
}
void solve()
{
    int n, k;
    std::cin >> n >> k;
    std::vector<Point> t(n);
    for (int i = 0; i < n; ++i)
    {
        std::cin >> t[i];
    }
    std::sort(begin(t), end(t), polarCmp);
    std::vector<Point> s(2 * n + 1);
    for (int i = 0; i < n; ++i)
    {
        s[i] = t[i];
        s[i + n] = t[i];
    }

    long double ans = 0;
    std::vector<int> vis(2 * n + 1, 0);

    int i = 0, j = 0;
    int cnt = 0;
    while (i < n)
    {
        while (i < n and s[i + 1] % s[i] == 0)
        {
            if (vis[i])
            {
                --cnt;
                vis[i] = 0;
            }
            ++i;
        }
        if (vis[i])
        {
            vis[i] = 0;
            --cnt;
        }
        if (j <= i)
        {
            j = i + 1;
        }
        while (j < n + i and cnt < k)
        {
            ++cnt;
            vis[j] = 1;
            ++j;
        }
        if (cnt < k)
        {
            ans = 2 * pi;
        }
        else
        {
            long double val = getAngle(BaseVector2(0, 0), s[i], s[j - 1]);
            if (val < 0)
            {
                val += 2 * pi;
            }
            ans = std::max(ans, val);
        }
        ++i;
    }
    std::cout << std::fixed << std::setprecision(20) << ans << '\n';
}
signed main()
{
    std::ios::sync_with_stdio(0);
    std::cin.tie(0);

    int t;
    std::cin >> t;
    while (t--)
    {
        solve();
    }
}